This invention relates generally to fluid transducers, and more particularly relates to fluid transducers incorporating an elliptical drive mechanism for converting rotary motion into reciprocatory motion, or vice versa. In one form of the invention the transducer can be utilized as an engine or motor to convert fluid-induced reciprocatory motion into rotary motion. In other forms of the invention, the transducer may be utilized as a pump or compressor to convert the rotary motion of a shaft into reciprocatory motion of a piston, to impart energy to a fluid through the motion of the piston.
There is a constant need in the fluid transducer field for an improved drive mechanism for transmitting energy to or receiving energy from a fluid through the efficient conversion of reciprocatory motion in to rotary motion, or vice versa. In standard reciprocating piston mechanism, for example, there are substantial motion and friction losses due to the need for crank shafts, connecting rods and the like.
Many prior attempts have been made to improve upon the standard crank shaft and connecting rod mechanism. For example, cam drive mechanisms have been designed which replace the standard crank shaft and connecting rods with a rotary drive cam and reciprocatory cam roller followers. Many of these prior cam drive mechanisms, however, still produce substantial motion and friction losses when transmitting motion betwen a reciprocating piston and a rotary shaft.
A substantial amount of these losses in prior mechanisms is due to the design of the drive cam and cam followers. Generally, the prior drive mechanisms use specially designed drive cams and circular roller cam followers, or other arrangements, which cause relative acceleration and deceleration and sliding friction to occur between the engaged parts. Such action produces motion and friction losses which decrease the operating efficiency of the drive mechanism.
It is therefore the principal object of this invention to provide an improved transducer drive mechanism which substantially reduces the foregoing motion and friction losses in converting reciprocating motion into rotary motion, or vice versa. According to this invention, the need for standard crank shafts and connecting rods is eliminated, and the problems experienced with earlier cam drive mechanisms are overcome, by providing a novel elliptical drive mechanism wherein the engaged rotary and reciprocatory components of the mechanism are elliptical in configuration. The engagement between the elliptical members in accordance with this invention is rolling contact which is substantially free of sliding friction and motion losses. The design of this invention produces such rolling contact by moving each of the engaged elliptical members with a constant angular velocity which precludes relative acceleration or deceleration of the engaged members.
Briefly described, the elliptical drive mechanism in accordance with this invention includes an elliptical member connected for rotation with a rotary member, such as a rotary input or output shaft. A second elliptical member is rotatably mounted in the transducer so that it is free to rotate, and to simultaneously reciprocate with a transducer piston member. The elliptical members are arranged to engage each other and rotate in unison as the piston reciprocates with respect to the rotary member. In an engine, the rotation of the shaft and the connected elliptical member causes rotation of the other engaged elliptical member in a manner which induces reciprocation of the connected piston. The opposite result occurs when the transducer is adapted for use as a compressor or a pump or the like. In such an arrangement, the reciprocation of the piston member causes the connected elliptical member to reciprocate and rotate, to thereby rotate the other engaged elliptical member and impart a rotary motion to the connected rotary member. Means are also provided in the transducer to maintain the elliptical members in driving engagement and to synchronize the relative rotation of the engaged elliptical members throughout these operations.